The field of art to which the invention pertains includes vehicular protective overhead guards.
Driver overhead guard structures have generally been adopted as standard equipment on lift trucks for the protection of operators from falling objects under specified conditions. It is of advantage to maximize standardization of chassis design within a given range of truck lifting capacities by including means for adjusting the truck frame or counterweight in a longitudinal direction as a function of the maximum load to be handled in any given truck operation. Various constructions have heretofore been devised for this purpose, a relevant one of which is disclosed in assignee's U.S. Pat. No. 3,061,034.
It is also of advantage to provide an overhead guard device for such vehicles which provides adjustment means for varying the effective length thereof, either in combination with a longitudinally adjustable counterweight, as in the above-mentioned patent, or for different trucks having different capacities whether the counterweight of any given such truck is adjustable or not, and to which such an adjustable overhead guard is adaptable.
A previous design for a longitudinally adjustable guard for the above purpose is disclosed in assignee's U.S. Pat. No. 3,687,484.